Newspaper Source: The Record, January 19, 2010 The article includes a picture of cars driving on route 4, and it discusses the problems drivers have been facing from the snow and ice storms. The article says that "several cars spun out, and fender benders punctuated the morning rush." Mass transit delays and slick roads were the main concerns of commuters, along with the obvious black ice and slush.
What Do You See? A crash dummy family is sitting in a wrecked car. It stimulates what happened to the car when the airbag absorbs the impact from the cement wall.
What Do You Think? By wearing a seatbelt, you can protect yourself in a car. Airbags can also protect you in the case of a severe accident. Usually cars come equipped with safety measures to increase chances of survival.
Investigate 1) 2A) Novice Analyst: Some seem obvious while others are just a guess. 9 out of 15 based on prior knowledge is pretty decent.
3)
Safety features
Means of protection
Pre-1960 cars
(yes/no)
New Cars
(1,2,3)
seat belts
To keep people from flying through the window like a projectile.
No
1
head restraints
When your head is snapped back from the impact, the head restraint holds your head back, just like in a roller coaster.
No
1
front airbags
The airbag keeps you from flying into the windshield.
No
1
back up sensing system
It's an option available in many new cars that allows the driver to hear a beeping noise when there is an object in your blind spot when backing up.
No
3
front crumple zones
When you crash, the car folds up like an accordion and is shock absorbent, protecting the passengers inside.
No
1, 2
rear crumple zones
Increase collision distance reducing impact
No
2
side-impact beams in doors
Resists side penetration
No
2
shoulder belts for all seats
Keeps passengers in seats during collision
No
1
anti-lock braking systems (ABS)
Helps avoid skidding in the case that the car loses friction
No
2
tempered shatterproof glass
Helps prevent cuts
Yes
1
side airbags
They help you avoid being slammed in the car doors
No
2
turn signals
Turn signals allow the other drivers to see where you are going in order to avoid an accident.
Yes
1
electronic stability control
Helps resists rollovers
No
2, 3
energy-absorbing collapsible steering column
Prevents chest trauma
No
1
Physics Talk, p263
1965: Ralph Nader wrote Unsafe at Any Speed
Looked at how safety was not a major consideration for the automobile industry
Since then, the industry has made a 180 in safety
An Australian study found the following:
The incidence of fatal accidents involving 4WD Vehicles increased by 85% between 1990 and 1998
Due to the growing number of kilometers the car was driven or that the safety features protect the driver 100%.
Incidence of fatal crashes decreased by 25% between 1990 and 1998
Checking Up 1) They added seat-belts, created collapsible steering columns and anti-lock brakes (ABS). 2) The incidence of fatal accidents involving 4WD Vehicles increased by 85% between 1990 and 1998 and in the incidence of fatal crashes decreased by 25% between 1990 and 1998.
What Do You Think Now? By using the safety measure provided for you, your increase of survival sky rockets. However, the simplest way to avoid getting into an accident is to drive slowly and cautiously.
Physics To Go, p265 1)
Safety features
F. R. S. T.
seat belts
F
head restraints
R
front airbags
F
front crumple zones
F
rear crumple zones
R
side-impact beams in doors
S
shoulder belts for all seats
F
side airbags
S
electronic stability control
T
energy-absorbing collapsible steering column
F
2) A helmet, knee pads, wrist pads, bicycle brakes, a well oiled chain, and tires that have the right amount of air in them with treads for traction. 3) A helmet, knee pads, wrist pads, a back stop brake, and hard plastic as a cast to protect your ankles from breaking. 4) A helmet, knee pads, wrist pads, and wheels that have traction.
Section 2
Investigate Objectives & Hypothesis:
What happens to a passenger involved in a car accident without and with a seatbelt?
When a passenger is not wearing a seatbelt, they become a projectile in the case of a head on collision. When they are wearing a seatbelt, they avoid flying through the windshield.
What factors affect the passenger’s safety after a collision?
Seat belts that are secured, and working airbags.
How would a seat belt for a race car be different from one available on a regular car?
The seat belt needs to be more complex to keep the passenger in the car, especially because of the extremely high speeds the car is traveling at.
Hypothesis:
I believe that our makeshift thread seatbelt will not keep the clay person in the vehicle, causing him to fly out like a projectile.
Materials: Clay, thread, tape, ramp, books, meter stick, and car.
Procedure:
Make a clay figure and then place the figure in the cart.
Arrange a ramp so that the endstop is at the bottom of the ramp.
Adjust the height of the ramp to make a very shallow incline.
Send the cart down the ramp.
Very gradually increase the height of the ramp until significant “injury” happens to your figure. Make a note of this height.
Fix your clay figure. Create a seatbelt for the figure and take a "Before" picture and post in your data table.
Send your cart and passenger down the ramp at the same height as in Step 5. Be sure to record your observations specifically and carefully. Take an "After" picture and post in your data table to supplement your written observations.
Repeat Steps 6 and 7, using different types of material for the seatbelt.
Data and observations: Injury Height with no seatbelt: 0.27 m
11Photo_43.jpg
Before (no seat belt)
11Photo_44.jpg
After (no seat belt) [head crushed] Injury Height with no seatbelt: .27 m
Type of Seatbelt
Before Picture
After Picture
Description and Observations
Group
Thread
111Photo_45.jpg
111Photo_46.jpg
Arm chopped off. The seat belt cut
through his body and sliced his neck. He also experienced severe head trauma; his head was crushed as seen in the picture above.
6
Wire
hershey_kissboybefore.jpg
hershey_kissboybefore.jpg
hersheykissafter.jpg
hersheykissafter.jpg
The wire was put around the passenger pretty tightly in order for him to stay on the cart after the collision. The wire was so tight that it sliced his arms and chest. The wire material is not a good idea because it can harm the person even if the collision wasnt that bad.
1
Yarn
sgrant22221.jpg
sgrant11.jpg
sgrant11.jpg
Our observation of the yarn seat belt is that when the accident occurred, the figure slammed forward. This shows that the yarn is not sturdy enough to prevent an injury in an accident.
7?
String
stringgPhoto_86.jpg
stringgPhoto_86.jpg
strringgPhoto_87.jpg
strringgPhoto_87.jpg
Our seatbelt made of string went around the chest. After going down the ramp, our passenger was still in the cart without any injuries.
2?
Ribbon
Photo_38lp.jpg
Photo_38lp.jpg
Photo_41lp.jpg
Photo_41lp.jpg
We made a seatbelt out of ribbon that went around his waist shoulders and chest. When the cart went down the ramp, the seatbelt held him in place and the clay person didn't leave the cart.
3
Tape
Photo_7758.jpg
Photo_7758.jpg
Photo_7662.jpg
Photo_7662.jpg
we took a piece of tape and folded it over so there was no sticky part. We then twirled the end to make tying it easier. We put the tape belt around "her" waist and tied it around the bottom of the cart. Despite my face in the after picture, the tape actually worked well because our figure was unharmed and barely moved.
4
Questions: 1) Define the terms: inertia, force and pressure.
Inertia: The natural tendency of an object to remain at rest or to remain moving with constant speed in a straight line.
Force: An interaction between two objects that result in an acceleration of either or both objects
Pressure: Force per area where the force is normal (perpendicular) to the surface; measured in N/m^2 or Pa (pascals)
2) In the collision, the car stops abruptly. What happens to the “passenger”?
The passenger flew out of the vehicle because our thread seatbelt was unable to keep him inside the car.
3) What parts of your passenger were in greatest danger (most damaged)?
Our person lost his hand at one point, as well as damaged his head multiple times.
4) What does Newton’s first law have to do with this?
Our person kept going down the ramp until something interacted with him and caused him to stop.
5) What materials were most effective as seatbelts? Why?
Ribbon and tape were the most effective because they were thicker and had more surface area to hold their clay models in the vehicle.
6) Use Newton's first law of motion to describe the three collisions.
A car hits an object (things in it keep moving)
Person hits seatbelt of car (organs keep moving)
Organs hit inside bone and ligaments
7) Why does a broad band of material work better as a seatbelt than a narrow wire?
The narrow wire can cut into him during the impact rather than stabilize them in the case of an accident.
Conclusion: 1) Using Newton's First law of Motion, explain why a seat belt is an important safety feature in a vehicle. What factors affect the effectiveness of a seatbelt? What would you need to consider when designing a seatbelt for a race car? Use specific observations from this investigation to support your answers to these questions.
The seatbelt keeps the person in the car and avoids being thrown into the windshield like a projectile. The width of the seatbelt and correct use of the shoulder strap allow the effectiveness of the seatbelt to be maximized. Based on the model from our experiment, you can see what happens when the seatbelt is too thin and does not exert enough force upon its user. When designing a seatbelt for a race car driver, I would make it similar to the ones found on a rollercoaster because the speeds are similar and allow maximum protection.
2) Explain at least 1 cause of experimental error. Be sure you describe a specific reason.
Experimental error be described as our seatbelt maybe working once really well, but the other times it didn't work. That first trial could have been our example of experimental error.
3) How would you improve the results of this lab? (In other words, what would you change about the materials or procedure to eliminate or reduce the experimental error you describe above?)
We would use a thicker seatbelt instead of thread. Although we wrapped the thread around him several times around his waist and then over his shoulder, it did not nearly exert the amount of force necessary to keep him from experiencing severe head trauma.
Section 3
Investigation Objective:How does an air bag protect you during an accident?
It slows you down before hitting the dashboard so that your organs don't smash into the inside of you.
Hypothesis:Air bags that have room for the air to move around allow for the safest protection.
Materials:Bag, meter stick, egg(s), flour, bowl
Procedure: 1. Measure the height of your egg #1. 2. Place an egg in a ziplock bag, squeezing out all of the air in the bag before sealing. 3. Hold a ruler up on the table vertically. Hold the egg vertically at the 2 cm mark. (Keep the excess bag on top.) Drop it. Record your observations. 4. Hold the egg the same exact way at the 4-cm mark and repeat. Continue this process until the egg shell is slightly cracked. 5. Continue until the egg is smashed and the yolk leaks out. Measure the amount of egg still undamaged. How much of the egg is smashed? Be sure to record detailed observations. 6. Fill a bowl with rice and place the bowl inside of the box lid. 7. Measure the height of your egg #2. 8. Drop the egg from the smash height (Step 3). Measure the amount of egg sticking up out of the rice bed. How much of the egg is buried in the rice? Also, record your observations. 9. Repeat this, increasing the height in 2-cm increments until the egg is cracked, and then smashed.
Data and observations: Add more columns/row as needed. Egg 1: 0.075 kg & 0.053 m
Egg #
Drop Height
Cracked or Smashed?
Description and Observations
How Deep
1
.02 m
very small crack
no visible crack but audible one
1
.04 m
small crack
visible and audible crack
1
.06 m
crack
visible, audible crack. Barely any liquid seeping out
1
.08 m
crack
hole in egg (membrane somewhat intact)
1
.1 m
bad crack
top flattened (liquid everywhere. no yoke yet)
1
.12 m
badder crack
everything is getting worse
1
.14 m
baddest crack
almost done
1
.16 m
awful crack
yoke isn't out (but things are bad)
1
.18 m
smashed
total annihilation
2
.18 m
perfect
nothing changed
.016 m
2
.2 m
perfect
nothing changed
.026 m
2
.24 m
no crack
nothing happened
.031 m
2
.28 m
no crack
nothing happened
.033 m
2
.32 m
no crack
nothing happened
.035 m
2
.36 m
no crack
nothing happened
.036 m
2
.4 m
no crack
nothing
.037 m
2
.44 m
no crack
nothing
.036 m
2
.5 m
no crack
nothing
.037 m
2
.6 m
no crack
nothing
.04 m
2
.7 m
no crack
nothing
.037 m
2
.8 m
no crack
nothing
.036 m
2
3 m
CRACK
CRACK
.045 m
Egg 1 (after accident): 0.041 m
Calculations: Show equation(s), numbers plugged in, and answer with correct units. Add columns in your data table to include these results.
What is the gravitational potential energy in each trial?
GPE = mgh
111Picture_1.png
How much work is done in each trial?
GPE = W
1111Picture_1.png
How much force was used to stop the egg in each case of steps 5, 8 and 9.
W = FD
W (J)
F (N)
D (m)
.106
6.625
.016
.118
4.54
.026
.141
4.55
.031
.165
5
.033
.188
5.37
.035
.212
5.89
.036
.235
6.35
.037
.259
7.19
.036
.294
7.95
.037
.353
8.825
.04
.412
11.14
.037
1.764
39.2
.045
Questions: 1) This investigate is an analogy for a person in an automobile collision. What does the egg represent? What does the table represent? What does the rice represent?
The egg represents a person whereas the bag acts as an airbag. It protects the body from the force due to a collision, as seen by the flour. The flour shows the exact impact, and the chart shows the distance the egg was dropped, its impact, and the damage done to the egg.
2) Define the terms: Kinetic Energy and Work.
Kinetic Energy: the energy possessed by a moving body is called kinetic energy. KE = 1/2(m)(v^2)
Work: the amount of force applied on an object over a distance; W = Fd
3) What factors determine an object's kinetic energy?
Mass and velocity effect an object's kinetic energy.
4) When work is done on an object, what is the effect on the object's kinetic energy?
When the force and distance are increased, so does the object's kinetic energy. The same goes for the decreasing work.
5) How does the force needed to stop a moving object depend on the distance the force acts?
1/2m(v^2) = fd
The force needs to increase to stop a moving object when the distance decreases.
6) What difference does a soft landing area make on a passenger during a collision?
The person is able to absorb the shock better if the landing area is soft
7) How does a cushion reduce the force needed to stop a passenger?
The cushion allows the body to move into the cushion (as shown in the video) and absorbs the impact.
8) What does the law of conservation of energy have to do with this?
It changes the amount of force over a distance of time.
Conclusion:
Using the law of conservation of energy, explain how an air bag can protect you during an accident. Use specific observations from this investigation to support your answers to these questions.
Because all of the energy from the forward momentum is countered by acting on something to stop it, more force needs to be applied. Air bags increase the distance slowing down and decrease the force.
Explain at least 1 cause of experimental error. Be sure you describe a specific reason.
Flours and egg cannot accurately parallel a person flying into a dashboard, and it does not show its effectiveness towards the human anatomy.
How would you improve the results of this lab? (In other words, what would you change about the materials or procedure to eliminate or reduce the experimental error you describe above?)
You can redo the test and see how fast a head will become injured without an airbag and compare the results.
Section 5
Investigation See Group Wiki
Physics Talk Momentum: quantity of motion described by the product of mass and velocity
mass x velocity
Large mass, small velocity
Small mass, large velocity
Large mass, large velocity
Physics To Go 1) Because the mass is equal and car #2 has velocity, the second car has much more momentum and damages car #1. 4) Those players have more mass, which means that it's harder to get through to the quarterback. Plus, the linemen have more momentum once they start going, which results in a harder hit. 5) The smaller car will get hit with the biggest impact due to its smaller mass in comparison to the large truck 6) mass x velocity = mass x velocity 1,000 x 10 = 10,000 x v 10,000 = 10,000(v) v = 1 m/s
Section 6
Investigation
Objective: What physics principles do the traffic-accident investigators use to "reconstruct" the accident?
They look at the mass and velocity of the objects involved in the investigation and use those numbers.
Materials: Ramp, motion detector, and 2 carts
Procedure:
Place a motion detector at the right end of a track. Open up data studio. Dump "Velocity" into "Graph" display, and enlarge this.
Place a cart on the middle of the track with the velcro to the right. Call this the "target cart." Place a second identical cart on the right end of the track. Call this the "Bullet cart".
Click "Start" on Data Studio, and then push the bullet cart very gently towards the target cart so that they collide and stick together. You may need to practice this a few times. Be sure to get your body out of the way of the motion detector!
Examine the graph produced by the motion detector. Using the Smart Tool, find the velocity right before and right after the collision. Record this in your data table.
Vary the masses of the carts and repeat the process 5 times.
Data and observations: Add more columns/row as needed.
Mass of Bullet Cart (kg)
Mass of Target Cart (kg)
Speed of Bullet Cart(m/s)
Speed of Target cart (m/s)
Combined masses (kg)
Final Velocity of both carts (m/s)
0.505
0.489
0.34
0
0.994
0.18
0.755
0.489
0.41
0
1.244
0.25
1.003
0.489
0.39
0
1.492
0.28
0.505
0.739
0.42
0
1.244
0.2
1.005
0.949
0.52
0
1.954
0.29
Calculations:Show equation(s), numbers plugged in, and answer with correct units. Add columns in your data table to include these results.
Momentum of Bullet Cart (mass x velocity) kg*m/s
Momentum of Target Cart (mass x velocity) kg*m/s
Sums of Initial Momenta
(mass1 + mass2)
Final Momentum (mass x velocity) kg*m/s
0.505(0.34) = 0.1717
0.489(0) = 0
0.1717
0.994(0.18) = 0.1789
0.755(0.41) = 0.3096
0.489(0) = 0
0.3096
1.224(0.25) = 0.306
1.003(0.39) = 0.3912
0.489(0) = 0
0.3912
1.492(0.28) = 0.4178
0.505(0.42) = 0.2121
0.739(0) = 0
0.2121
1.244(0.2) = 0.2488
1.005(0.52) = 0.5226
0.949(0) = 0
0.5226
1.954(0.29) = 0.5667
Questions: 1) Compare the initial momenta (calc 3) to the final momentum (calc 4). (Allow for minor variations due to uncertainties of measurement.)
The two calculations are surprisingly pretty close to one another. The initial momenta is a little smaller than the final momentum, but not by much.
2) List the 6 types of collisions (top of page 312) and a brief description.
A moving object hits a non-moving object and they move together at the same speed
Two objects spring away from one another
A moving object hits a non-moving object and transfers all of its momentum to the stationary one
A moving object hits a stationary object and they bounce off at different speeds
Two objects hit one another and go off at different speeds
Two objects hit and move at the same speed
3) Which types of collisions are definitely inelastic? How do you know?
Types 2, 4, and 5 are all kinetic energy and therefore are not elastic.
4) Which types of collisions are definitely elastic? How do you know?
Types 1, 3, and 6 do not show a change in kinetic energy, which makes them elastic.
5) Define the law of conservation of momentum.
Law of Conservation of Momentum: the total momentum before a collision is equal to the total momentum after the collision if no external forces act on the system.
6) Use the law of conservation of momentum to describe what happens when a cue ball hits the 15 balls in the middle of the pool table.
The stick hits the cue ball quickly, and that momentum is transferred onto the first ball it hits. That ball hits the rest of the triangle, and the balls' velocities are then slower as a result of the momentum being shared through all of the balls.
Conclusion: 1) Based on the law of conservation of momentum, how can the traffic-accident investigators use to "reconstruct" the accident? What does it mean to "conserve" momentum?
Investigators are able to look how how the momentum was transferred between cars and decide who is to blame.
2) Explain at least 1 cause of experimental error. Be sure you describe a specific reason.
Weather conditions could be of experimental error, as they alter speeds.
3) How would you improve the results of this lab? (In other words, what would you change about the materials or procedure to eliminate or reduce the experimental error you describe above?)
I would actually add elements to make the ramp slick to see if that changed the velocity or momentum of the car.
Physics to Go 2A) Cart 1 p = mv p = 1(2) p = 2 kg*m/s Cart 2 p = mv p = 1(-2) p = -2 kg*m/s 2B) p(total) = p(cart 1) + p(cart 2) p = 2 - 2 p = 0 kg*m/s 2C) P(total) = P(cart 1) + P(cart 2) P = -2 + 2 P = 0 kg*m/s 3) p(car 1) + p(car 2) = 4 m/s (2m) mv(car 1) + mv(car 2) = 4 m/s (2m) v(car 1) + v(car 2) = 8 m/s v(car 1) + 0 = 8 m/s v(car 1) = 8 m/s 5) 4,000 kg*m/s and a total change of 0 kg*m/s during the collision because car A gives all of its momentum to car B. 6) p(cart 1) + p(cart 2) = p(total) mv(cart 1) + mv(cart 2) = mv (total) 2000(3) + (2000)(2) = (4000)(v) v = 2.5 m/s 7) p(player 1) + p(player 2) = p(player 1) + p(player 2) mv(player 1) + mv(player 2) = mv (player 1) + mv (player 2) 80(10) + 100(8) = 80(v) + 100(9.78) 7.8 m/s = v in same direction 8) p(ball 1) + p(ball 2) = p(ball 1) + p(ball 2) mv(ball 1) + mv(ball 2) = mv (ball 1) + mv (ball 2) 3(2) + 1(-2) = 3(0) + 1(v) v = 4 m/s
Table of Contents
Section 1
Newspaper Source: The Record, January 19, 2010
The article includes a picture of cars driving on route 4, and it discusses the problems drivers have been facing from the snow and ice storms. The article says that "several cars spun out, and fender benders punctuated the morning rush." Mass transit delays and slick roads were the main concerns of commuters, along with the obvious black ice and slush.
What Do You See?
A crash dummy family is sitting in a wrecked car. It stimulates what happened to the car when the airbag absorbs the impact from the cement wall.
What Do You Think?
By wearing a seatbelt, you can protect yourself in a car. Airbags can also protect you in the case of a severe accident. Usually cars come equipped with safety measures to increase chances of survival.
Investigate
1)
2A) Novice Analyst: Some seem obvious while others are just a guess. 9 out of 15 based on prior knowledge is pretty decent.
3)
(yes/no)
(1,2,3)
Physics Talk, p263
Checking Up
1) They added seat-belts, created collapsible steering columns and anti-lock brakes (ABS).
2) The incidence of fatal accidents involving 4WD Vehicles increased by 85% between 1990 and 1998 and in the incidence of fatal crashes decreased by 25% between 1990 and 1998.
What Do You Think Now?
By using the safety measure provided for you, your increase of survival sky rockets. However, the simplest way to avoid getting into an accident is to drive slowly and cautiously.
Physics To Go, p265
1)
3) A helmet, knee pads, wrist pads, a back stop brake, and hard plastic as a cast to protect your ankles from breaking.
4) A helmet, knee pads, wrist pads, and wheels that have traction.
Section 2
InvestigateObjectives & Hypothesis:
Hypothesis:
Materials: Clay, thread, tape, ramp, books, meter stick, and car.
Procedure:
Data and observations:
Injury Height with no seatbelt: 0.27 m
Before (no seat belt)
After (no seat belt) [head crushed]
Injury Height with no seatbelt: .27 m
through his body and sliced his neck. He also experienced severe head trauma; his head was crushed as seen in the picture above.
Questions:
1) Define the terms: inertia, force and pressure.
- Inertia: The natural tendency of an object to remain at rest or to remain moving with constant speed in a straight line.
- Force: An interaction between two objects that result in an acceleration of either or both objects
- Pressure: Force per area where the force is normal (perpendicular) to the surface; measured in N/m^2 or Pa (pascals)
2) In the collision, the car stops abruptly. What happens to the “passenger”?- The passenger flew out of the vehicle because our thread seatbelt was unable to keep him inside the car.
3) What parts of your passenger were in greatest danger (most damaged)?- Our person lost his hand at one point, as well as damaged his head multiple times.
4) What does Newton’s first law have to do with this?- Our person kept going down the ramp until something interacted with him and caused him to stop.
5) What materials were most effective as seatbelts? Why?- Ribbon and tape were the most effective because they were thicker and had more surface area to hold their clay models in the vehicle.
6) Use Newton's first law of motion to describe the three collisions.- A car hits an object (things in it keep moving)
- Person hits seatbelt of car (organs keep moving)
- Organs hit inside bone and ligaments
7) Why does a broad band of material work better as a seatbelt than a narrow wire?Conclusion:
1) Using Newton's First law of Motion, explain why a seat belt is an important safety feature in a vehicle. What factors affect the effectiveness of a seatbelt? What would you need to consider when designing a seatbelt for a race car? Use specific observations from this investigation to support your answers to these questions.
- The seatbelt keeps the person in the car and avoids being thrown into the windshield like a projectile. The width of the seatbelt and correct use of the shoulder strap allow the effectiveness of the seatbelt to be maximized. Based on the model from our experiment, you can see what happens when the seatbelt is too thin and does not exert enough force upon its user. When designing a seatbelt for a race car driver, I would make it similar to the ones found on a rollercoaster because the speeds are similar and allow maximum protection.
2) Explain at least 1 cause of experimental error. Be sure you describe a specific reason.- Experimental error be described as our seatbelt maybe working once really well, but the other times it didn't work. That first trial could have been our example of experimental error.
3) How would you improve the results of this lab? (In other words, what would you change about the materials or procedure to eliminate or reduce the experimental error you describe above?)Section 3
Investigation
Objective: How does an air bag protect you during an accident?
Hypothesis: Air bags that have room for the air to move around allow for the safest protection.
Materials: Bag, meter stick, egg(s), flour, bowl
Procedure:
1. Measure the height of your egg #1.
2. Place an egg in a ziplock bag, squeezing out all of the air in the bag before sealing.
3. Hold a ruler up on the table vertically. Hold the egg vertically at the 2 cm mark. (Keep the excess bag on top.) Drop it. Record your observations.
4. Hold the egg the same exact way at the 4-cm mark and repeat. Continue this process until the egg shell is slightly cracked.
5. Continue until the egg is smashed and the yolk leaks out. Measure the amount of egg still undamaged. How much of the egg is smashed? Be sure to record detailed observations.
6. Fill a bowl with rice and place the bowl inside of the box lid.
7. Measure the height of your egg #2.
8. Drop the egg from the smash height (Step 3). Measure the amount of egg sticking up out of the rice bed. How much of the egg is buried in the rice? Also, record your observations.
9. Repeat this, increasing the height in 2-cm increments until the egg is cracked, and then smashed.
Data and observations: Add more columns/row as needed.
Egg 1: 0.075 kg & 0.053 m
Egg 1 (after accident): 0.041 m
Calculations: Show equation(s), numbers plugged in, and answer with correct units. Add columns in your data table to include these results.
- What is the gravitational potential energy in each trial?
GPE = mgh- How much work is done in each trial?
GPE = W- How much force was used to stop the egg in each case of steps 5, 8 and 9.
W = FD1) This investigate is an analogy for a person in an automobile collision. What does the egg represent? What does the table represent? What does the rice represent?
- The egg represents a person whereas the bag acts as an airbag. It protects the body from the force due to a collision, as seen by the flour. The flour shows the exact impact, and the chart shows the distance the egg was dropped, its impact, and the damage done to the egg.
2) Define the terms: Kinetic Energy and Work.- Kinetic Energy: the energy possessed by a moving body is called kinetic energy. KE = 1/2(m)(v^2)
- Work: the amount of force applied on an object over a distance; W = Fd
3) What factors determine an object's kinetic energy?- Mass and velocity effect an object's kinetic energy.
4) When work is done on an object, what is the effect on the object's kinetic energy?- When the force and distance are increased, so does the object's kinetic energy. The same goes for the decreasing work.
5) How does the force needed to stop a moving object depend on the distance the force acts?- 1/2m(v^2) = fd
- The force needs to increase to stop a moving object when the distance decreases.
6) What difference does a soft landing area make on a passenger during a collision?- The person is able to absorb the shock better if the landing area is soft
7) How does a cushion reduce the force needed to stop a passenger?- The cushion allows the body to move into the cushion (as shown in the video) and absorbs the impact.
8) What does the law of conservation of energy have to do with this?Conclusion:
Section 5
InvestigationSee Group Wiki
Physics Talk
Momentum: quantity of motion described by the product of mass and velocity
Physics To Go
1) Because the mass is equal and car #2 has velocity, the second car has much more momentum and damages car #1.
4) Those players have more mass, which means that it's harder to get through to the quarterback. Plus, the linemen have more momentum once they start going, which results in a harder hit.
5) The smaller car will get hit with the biggest impact due to its smaller mass in comparison to the large truck
6) mass x velocity = mass x velocity
1,000 x 10 = 10,000 x v
10,000 = 10,000(v)
v = 1 m/s
Section 6
InvestigationObjective: What physics principles do the traffic-accident investigators use to "reconstruct" the accident?
Materials: Ramp, motion detector, and 2 carts
Procedure:
Data and observations: Add more columns/row as needed.
Calculations: Show equation(s), numbers plugged in, and answer with correct units. Add columns in your data table to include these results.
(mass1 + mass2)
Questions:
1) Compare the initial momenta (calc 3) to the final momentum (calc 4). (Allow for minor variations due to uncertainties of measurement.)
- The two calculations are surprisingly pretty close to one another. The initial momenta is a little smaller than the final momentum, but not by much.
2) List the 6 types of collisions (top of page 312) and a brief description.- A moving object hits a non-moving object and they move together at the same speed
- Two objects spring away from one another
- A moving object hits a non-moving object and transfers all of its momentum to the stationary one
- A moving object hits a stationary object and they bounce off at different speeds
- Two objects hit one another and go off at different speeds
- Two objects hit and move at the same speed
3) Which types of collisions are definitely inelastic? How do you know?- Types 2, 4, and 5 are all kinetic energy and therefore are not elastic.
4) Which types of collisions are definitely elastic? How do you know?- Types 1, 3, and 6 do not show a change in kinetic energy, which makes them elastic.
5) Define the law of conservation of momentum.- Law of Conservation of Momentum: the total momentum before a collision is equal to the total momentum after the collision if no external forces act on the system.
6) Use the law of conservation of momentum to describe what happens when a cue ball hits the 15 balls in the middle of the pool table.Conclusion:
1) Based on the law of conservation of momentum, how can the traffic-accident investigators use to "reconstruct" the accident? What does it mean to "conserve" momentum?
- Investigators are able to look how how the momentum was transferred between cars and decide who is to blame.
2) Explain at least 1 cause of experimental error. Be sure you describe a specific reason.- Weather conditions could be of experimental error, as they alter speeds.
3) How would you improve the results of this lab? (In other words, what would you change about the materials or procedure to eliminate or reduce the experimental error you describe above?)Physics to Go
2A) Cart 1
p = mv
p = 1(2)
p = 2 kg*m/s
Cart 2
p = mv
p = 1(-2)
p = -2 kg*m/s
2B) p(total) = p(cart 1) + p(cart 2)
p = 2 - 2
p = 0 kg*m/s
2C) P(total) = P(cart 1) + P(cart 2)
P = -2 + 2
P = 0 kg*m/s
3) p(car 1) + p(car 2) = 4 m/s (2m)
mv(car 1) + mv(car 2) = 4 m/s (2m)
v(car 1) + v(car 2) = 8 m/s
v(car 1) + 0 = 8 m/s
v(car 1) = 8 m/s
5) 4,000 kg*m/s and a total change of 0 kg*m/s during the collision because car A gives all of its momentum to car B.
6) p(cart 1) + p(cart 2) = p(total)
mv(cart 1) + mv(cart 2) = mv (total)
2000(3) + (2000)(2) = (4000)(v)
v = 2.5 m/s
7) p(player 1) + p(player 2) = p(player 1) + p(player 2)
mv(player 1) + mv(player 2) = mv (player 1) + mv (player 2)
80(10) + 100(8) = 80(v) + 100(9.78)
7.8 m/s = v in same direction
8) p(ball 1) + p(ball 2) = p(ball 1) + p(ball 2)
mv(ball 1) + mv(ball 2) = mv (ball 1) + mv (ball 2)
3(2) + 1(-2) = 3(0) + 1(v)
v = 4 m/s
Section 7
Investigation
See Group Wiki